Headless nail



May 29, 1956 c. M. LINDSTROM HEADLESS NAIL.

Filed Dec. 16. 1952 7. [I2 dezzlor li'arn qys CjzarlesMLmd'shom z a M United States Fate'nt C HEADLESS NAIL Charles M. Lindstrom, Westerly, R. 1., assignor to Bostitch, Inc., Stonington, Conn., a corporation of Rhode Island Application December 16, 1952, Serial No. 326,234

2 Claims. (CI. 85-10) This invention relates to fastener devices for attaching various objects and articles and more particularly to a preformed bridgeless staple of inverted V-shape having divergent legs adapted to be bent into parallel, contiguous relationship before driving to provide a headless brad, tack or nail.

One object of the invention is to provide a preformed headless staple having divergent legs connected at the top by relatively short sections extending in parallel contiguous relationship above their divergent portions so that said legs may be forced together in alinement with their upper parallel portions to provide a headless brad, tack or nail.

Another object is to provide a headless brad, tack or nail formed from a length of wire bent intermediate its ends into a narrow loop with the sides of the loop in contiguous, parallel relationship and continued downward in a pair of legs spread apart in divergent relationship and adapted to be forced together in alinement with the sides of the loop before driving the brad into the work.

Another object is to provide a preformed staple having divergent legs and so constructed and arranged that it may be finally formed into a headless brad in a stapling or tacking machine with the opposite legs in contact throughout their length below the looped connecting portion without causing spreading of the legs at their point of joinder.

Another object is to provide a method of preforming a wire staple by bending or doubling a length of wire on itself intermediate its ends in the form of a closed loop having parallel contiguous side portions and then bending the main portion of the legs below the loop into divergent relationship so that finally they may be brought together in alinement with the sides of the'loop to form a headless brad, tack or nail.

Another object is to provide a preformed staple of inverted V-shape which may be finally shaped with its opposite legs closely connected together at the top without a crown or crossbar and extending throughout their length in parallel contiguous relationship. 7

Another object is to provide a headless brad, tack or nail for use in fastening laminations of wood or other strips and adapted to be countersunk in the material in which it is driven without marring the exposed surface thereof.

The following specification describes the invention as embodied in a preformed staple with a preferred method of constructing the staple from wire or thin strips of metal and finally shaping it as a headless brad, tack or nail prior to driving it into the work. The invention is illustrated by the accompanying drawing in which:

Fig. 1 is a perspective view of a portion of a strip or stick of connected staples constructed in accordance with the invention;

Fig. 2 is an enlarged end view of a staple of inverted V-shape, constructed in accordance with the invention and illustrating in dash-lines the manner in which it is finally formed with its legs in parallel contiguous relationship throughout their full length;

" ice Fig. 3 is an end view of the staple strip or refill illustrated in Fig. 1 showing it as mounted on a tapered core or support shown in section as shaped to the configuration of the staples in the strip;

Fig. 4 is a sectional view of several layers of material shown as fastened together by the present improved headless brad formed from a staple of the present Fig. 5 is a part-sectional end view of the operating parts of a stapling implement which may be used for closing together the legs of the staple before driving it into the work;

Fig. 6 is a similar view showing the staple-bending means as having been operated to straighten and close together the legs of the staple; and

Fig. 7 is a similar view showing the headless brad or nail formed from the staple as being driven into the work.

It has previously been proposed to provide a wire staple having divergent legs connected at the top by an arcuate looped portion of the wire. When staples of such shape finally have their legs bent into parallelism the legs are spaced apart a distance twice the length of'the radius of the arcuate connecting portion of the Wire at the top so that there will be a considerable opening or space between the parallel legs. In other words, when the legs of such staple are finally bent into parallel relationship they will be spaced apart by the connecting crown-portions and therefore cannot be used as headless brads, tacks or nails. It is a principal object of the present invention to so preform the staple at the joinder of its legs that eventually the legs can be bent or straightened to lie in parallel contiguous relationship throughout their length. With the present improved preformed staple the legs can be brought together into parallel contiguous relationship without a space therebetween and with no lateral projecting portions at the top, that is, it is rendered bridgeless in the form of a headless brad or nail.

Referring first to Fig. 1, the present improved preformed staple 2 may be constructed of wire or thin strip material by first bending or folding the wire or strip at a point between its ends, preferably midway therebetween, so as to provide a pair of divergent legs 3 of equal length. Usually, the ends of the legs are beveled to sharpen their terminal points for ease in driving. During, or subsequent to, the first bending operation the wire in the sides 4 of the loop is pressed or swaged together to close the loop; that is, force its sides into close abutting relationship for a relatively short distance indicated by the line a in Fig. 1. The length of the upper closely abutting portions 4 of the staple legs is shown in the drawing as approximately one-sixth of the full length of the staple, but these proportions may be varied as desired, for example, by either shortening or lengthening the diverging portions 3 of the legs.

The preforming of the staples may be accomplished in suitable dies or swaging tools, either operating on the staples individually or when joined together in a.

tively short length of the legs into parallel contiguous relationship.

The staples may be supplied to a stapling implement by straddling the strip or stick across a core or support 5, shown in Fig. 5, which extends longitudinally of the magazine of such a type of implement embodying means for feeding the whole strip forwardly to advance the foremost staple into position to be driven. Means for finally bending together the divergent legs 3 of the staple are a Q Letters Patent for Fastener-ApplyingImplement, Patent No. 2,714,207, dated August 2, 1955. In theinvention of this patent the head of the implement is provided in its basewith a relatively narrow throat opening through the top just below the staple-supporting core 5. The opening 11 at the top of the throat or passage 10 is preferably beveled slightly on thesides to provide an easy entrance for the staple-as it is driven down'into the throat. The fastener-applying implement is provided with a reciprocablc staple driver 12 of the 'plungertype haviii'g'its'l'ower portion formed into a thin blade 13 dimensioned 'to adapt it to slide through the throat "10. I

The above-described implement is pro'vided with benderlevers 15, so called, pivoted onstuds 16 and mounting pins 17 at the top'which, form journals for apair of rollers 18 engaging in cam-grooves 20411 a block-likemember 21.j The member 21 is attached to, or formed as apart of, a slidablesleeve 22 adapted to he 'r'eipro cat'ed vertically of the implement, this. part of the mechanismbeing illustrated and described more'tullyin' my prior application identified above.

When the sleeve 22 is slid downwardly on the head of the stapling implement the block-like member 21 descends with it to cause the rollers 1 8 on the studs 16 to ride upwardly in the cam-groove 20. The cam-grooves are of substantially"L-shape, as 'indicated by dotted lines in Figs. 5 to 7, so that as the rollers '18travel upwardly therein the upper'arrns of the'levers 15 are forced apart to move their lower arms together as shownin Fig. 6.

This rocking motion of the levers 15 causes their lower arms to impinge against the divergent legs -3 of each staple after it is fed off from the forward end of the core 5, thereby forcing the legs of the staple together' into parallel abutting relationship. After the above-described operation of the bender-levers 15 'for closing tog'ether-the legs of the stable, the driver 12 descends with its blade 13 passing between the opposing faces of the levers to drive the staple downwardly through the throat 10 'and outwardly therefrom for inserting it'into thework W. As shown-in Fig. 4, the work W may consist ofa board or backing'B overlaid with a plurality of laminations b, or the work may 'be of any other'nature'in which parts are to be held together by'headless brads, 'tacks or nails.

The present improved staple in its final form is particularly adapted for use as'a brad for fastening'together the parts of furniture, such as the front and Sides of a drawer for a desk or table, and for many other uses where several layers of wood 'or the like aret'o be held together; the brad or nail being headless to adapt'it tobe countersunk and provide a practically invisible fastening After the headless brador nairrerm'eu from the present improved staple'has been driveninto'thework'the driverbl'a'de 13 is withdrawn and the earn-block 21 raised'whereby the rollers 18 on the studs 17 are'caus'ed' to travel down the inclined portions of the cam-grooves 29 to draw 'into contact-and remain contiguous for driving it into the work. The 'upper:-portions of 'the legs of the staple where connected at the top will also'lie in contiguous abutting relationship without projecting laterally'to; f'o'rm'an obstruction or head when the brad is countersunk in the I work.

The present method of forming the closed looped portions of the staple legs also has an important advantage in that when the legs are finally brought together by a bending operation they will have less tendency to spring apart due to the nature of 'the 'rnaterial, such as the tempered wire from which they are constructed. Stated another way, the'legs'of the staple will remain closed" together in abutting relationship both while the staple is driven and after it has been-applied to the work; and due to the fact that it has no projections at the top, that is being headless, it will not abrade, split or otherwise injure materials through which it is driven when p the brad is countersunk beneath the upper surface of the work. As another advantage, the parallel legs being infull contact act to stiffen and reinfo'rce eachother to prevent them from bending or buckling. It is believed that thepresent invention embodies a noveland original method of preforming a staple with divergent'legs in such manner thatthe'legs may'be broughttogether in parallel abutting relationship throughout their full length and caused to remain. in this form during application of the finishedbrad, tack or nail in the work.

Whilethe present specification and drawing illustrate the'present improved staple as of conventional dimensions with a preferred proportion of the length of its preformed upper portion to the full length of the legs, these dimensions are subject torv'aiiation in accordance with requirements in use. Likewise, .the thickness or width of the stock from which the staple is constructed may be varied at will and other moditications made within the purview of theptesent invention. Therefore, without limiting myself in this respect,'I claim:

1. An improved staple having opposite legs of substantially uniform cross-section joined together at the top in a closed loop with the "sides of said loop'in contiguous abutting relationship, throughout a relatively short portion of-the length of thelegs and extending in parallelism with a median vertical plane, the remaining relatively long portions ofthe legsbeing ofequal length diverging at an 2. An improved staple having opposite legs of substan- V tially unitorm cross-sectionjoined together at the. top'in a closed loop with the sidesof said loop in contiguous abutting relationship throughout relativ'elyishort portions of the length of the legs and extending. in parallelism with a median vertical plane, the remaining relatively long portions of'the legs being of equal length diverging at an angle to each other, said 'loopat all times being within the lateral width of said legs whereby a headless brad is formed, and the terminal end of each leg being beveled at least on'the outsideto provide a sharp point whereby to cause the legs-to retain their close abutting relationship without spreading apartas the staple is driven in'the-form of a headless brad.

References Cited in the fileof this patent UNITED STATES PATENTS 

